The present invention relates to the field of heat shrinkable tubular articles such as sleeves and the use thereof. More specifically, the invention provides an improved lubricant and method of using the lubricant, especially in conjunction with the application of heat shrinkable sleeves to electrical wires and cables.
Heat shrinkable sleeves and their use are well known. For example, heat shrinkable sleeves and associated devices are disclosed in the U.S. Pat. Nos. 3,894,731, 4,868,023, 4,712,721, 4,478,252, 4,349,404, 3,894,731, 2,027,962, 4,969,402, and 4,514,031, all incorporated herein by reference for all purposes. Such sleeves are used, for example, to protect cable splices from environmental attack, and to provide visual markings for identification of a particular wire or group of wires. Commercially, such sleeves are represented by the Thermofit.RTM. marker system manufactured by the assignee of the present invention.
One method of applying heat shrinkable sleeves (i.e., short lengths of tubing) to wires or cables involves the use of a carrier of the sleeves such as a bandolier. Heat shrinkable sleeves are affixed to the bandolier for ease of handling. The bandolier enables markkng of the heat shrinkable sleeves for later installation on and identification of a particular cable or wire. A technician can easily slide the sleeve off of the bandolier, and apply the marked sleeve to a cable or wire. The sleeve may then be heated or otherwise treated at a later convenient time so as to firmly attach it to the wire or cable and/or to permatize the indicia marked on it.
The sleeve is preferably sized such that it fits snugly on the bandolier to prevent sliding off of the sleeve before it is marked. However, if the sleeve fits too snugly on the bandolier, removal of the sleeve from the bandolier is sometimes difficult. Accordingly, various lubricants have been applied to the sleeve and/or the bandolier to facilitate removal of the sleeve.
Most commonly, such lubricants have been applied by dispersing the lubricant in a suitable organic carrier and applying the dispersed lubricant to the inner surface of the sleeve and/or to the outer surface of the bandolier. Normally such lubricants are dispersed in a low boiling point chlorofluorocarbon such as material marketed under the name Freon*. FNT *a trade mark of du Pont Corporation
Recently, problems have arisen with the use of such chlorofluorocarbons. Importantly, it has been asserted that chlorofluorocarbons present an environmental threat, primarily resulting from ozone depletion. Accordingly, many industries are attempting to reduce or eliminate the use of chlorofluorocarbons to abate global warming and ozone depletion. Efforts to replace chlorofluorocarbons have, however, been directed primarily at the largest volume users of such materials. For example, replacements for Freon as a refrigerant, and replacements for the various chlorofluorocarbons used in the electronic industry as cleaning solvents have been proposed. These efforts have not addressed in a substantial way the needs of industries which use chlorofluorocarbons as a lubricant carrier, however.
From the above it is seen that an improved composition and method for lubricating parts such as heat shrinkable sleeves is needed.